Role of lateral preoptic area alpha-1 and alpha-2 adrenoceptors in sleep-wakefulness and body temperature regulation.

The preoptic area is anatomically divided into medial and lateral portions and both are involved in the regulation of sleep-wakefulness and body temperature. We have recently reported the specific role of the adrenoceptors, present in the medial preoptic area, in the regulation of those functions. In this study an attempt was made to investigate the specific participation and contribution of the lateral preoptic area alpha-1 and alpha-2 adrenoceptors in the regulation of sleep-wakefulness and body temperature. Sleep-wakefulness and rectal temperature were simultaneously recorded in freely moving rats, both during day and night, under normal condition and after bilateral local microinjection of either agonist or antagonist of alpha-1 and alpha-2 adrenoceptors into the lateral preoptic area. The results suggest that the lateral preoptic area alpha-2 adrenoceptors are predominantly involved in the regulation of sleep-wakefulness whereas alpha-1 adrenoceptors are more effective in thermoregulation.